After 7.5 years with my INTJ wife, we haven't noticed any pitfalls. The only risk containment we've had to learn to practice is making sure that we don't each make plans that don't dovetail. Having both spent most of our lives with P's, we're both accustomed to being in charge of planning. This may have more to do with our biographies than with the nature of INTJ's or INTJ-INTJ relationships.

One of the possibly less obvious good points is that we truly think alike most of the time, even on individually trivial, everyday decisions such as what to have for breakfast, where to go on vacation, what DVD to watch or who to invite over for dinner.

A possibly more obvious good point is that we both mean what we say at all times. This has enormous advantages in a relationship. "I don't know" means "the person uttering this sentence does not have cognitive access to the answer in any way". It doesn't mean "I know, but I'm not going to tell you yet because it's good for you to see that I know something you don't", nor "I know, but I don't want to tell you because it might hurt your feelings", nor "I know, but I don't want to tell you because it hurts my feelings", nor "I know, but I don't want to tell you because I'm sure you'll disagree", nor "I don't know, but I could look it up on my cellphone if I felt like it, which I don't", nor "I may or may not know, but I'm going to the mall now", nor "Mommy!!!! Help me!!!!! Somebody asked me a question!!!!! HEEEEEELP!!!!!!", nor "I don't know, but I can make up something really plausible for you real quick".

Hmm..
>The only risk containment we've had to learn to practice is making sure that we don't each make plans that don't dovetail.
I have found this next to impossible to achieve with my INTJ coworkers;
I can only guess how much more difficult it would be when you share a household.
It is diffiicult to determine who should make the plans for a particular instance especialy in cases when neither side has explicit expertise. Does this in practice mean you have to hold of some decisions untill both of you can discuss it?

The Obvious benefit was supposed to be the common mindset.
You mentioned this was less obvious?!? ( Do I detect some sarcasm here?)

Your second point was less obvious to me but is by far much more important.
In short, your conversations are free from emotional games (blackmail).

Whenever I had INTJ coworkers, I was in charge at the time so the problem didn't materialize. One time I did have two INTJ team members who were planning right past each other until we all got on track. ("I'm the system architect!" ... "Yeah, but I'm the lead designer!") This was at a Fortune-10 corporation whose name I've forgotten, and the problem was the same as usual: no org chart. I don't see it as the INTJ's's fault. (INTJ's never make mistakes, as you know.)

In the household, we generally plan everything together except in areas that are clearly in her or my bailiwick. Not having any kids makes the planning orders of magnitude less complicated, of course...

And what's really fun is communication by soundbyte...this has less to do with mindset than by the fact that most of the INTJ's we know all seem to like the same movies, books, etc. I have no real answer as to why that's so, except quantum entanglement.

Telepathy's next.

Leane Roffey Line, Ph.D.

INTJ: There is no spoon.
ENFP: I have a spoon, wanna see? Oh, wait a minute, I left it in the car. Hey, as long as we have to go to the car, wanna take a drive? Oh, isn't my car just the prettiest thing you've ever seen? Hold on, I forgot my purse. Oh, let's go to the mall. We can get a new spoon there.